1. Field of the Invention
The present invention relates to electrical connectors used to electrically couple two electronic boards or devices together.
2. Description of Related Art
Computers or other similar type electronic systems will typically have discrete electrical devices soldered to printed circuit boards (PCB's). The devices are usually packaged in plastic carriers that have copper leads which extend through the printed circuit boards, to provide an electrical connection between the device and the PCB. Routing space for the conductors within the PCB is reduced because the lines must go around the leads extending through the board. To increase routing density, methods have been devised to mount the devices onto the surface of the PCB's, without the extended leads and accompanying plated through holes in the boards. One common method of surface mounting components, is to provide electrically conductive pads on the surface of the PCB and wave soldering the components to the pads. Because there are no leads extending through the board it is now possible to mount components on both sides of the board, greatly increasing the electronic density of the board.
An assembled PCB will typically communicate with other electrical devices such as a computer keyboard, a printer, or another board. This is usually done with a pair of mating connectors, wherein the connectors have electrically conductive leads that are soldered to the PCB. The leads are wave soldered to the boards in the same manner as the components. Usually the connector is attached to the PCB after the components have already been soldered to the board. To solder the connector, the whole board must be raised to the solder melting point. When a connector is soldered to a board with components on both sides, the components of the board facing down fall off the board. Additionally, every time the board is subjected to wave soldering the PCB is degraded, especially the surface pads. It is therefore desirable to have an electrical connector that can interconnect a PCB and another electrical device without soldering the conductors to the PCB. Repairing the connector is also difficult, wherein the board must again be reflowed. This requires moving the board to a wave solder machine, which is large, expensive and usually only found in manufacturing facilities. It would be preferable to remove the connectors "on site", without the need for a soldering device.
The ever increasing capacity of integrated circuits and routing of the PCB's has greatly increased the input/output (I/O) requirements of the connectors. Standard connectors are typically constructed with 0.100 inch centers, with some "high density" connectors having 0.050 inch centers. It has been found that such connectors are insufficient to handle the I/O requirements of some of the present computer systems being designed. It would therefore be desirable to have a connector that has spacing lower than 0.050 inches.